Hormone Receptors and Cancer

Vocabulary flashcards covering hormone receptor signaling, diagnostic tools, resistance mechanisms, and therapeutic strategies in androgen- and estrogen-dependent cancers based on Medical Biochemistry lecture content.

Prostate Gland

A small gland found only in men that surrounds the urethra, requires androgen signalling for cell survival and apoptosis, and produces a thick, white fluid that mixes with sperm to create semen.

Prostate Cancer

A carcinoma of the prostate gland that can multiply, form a tumour, and metastasize to surrounding organs or distant sites, particularly bones and lymph nodes.

Carcinoma in Situ

An early stage of cancer where small lumps of cancer cells remain confined within their tissue of origin (such as the prostate gland or breast ducts) before invading surrounding structures.

Prostate Specific Antigen (PSA)

A protein produced by the prostate gland whose elevated levels in blood tests indicate potential early stages of prostate cancer or prostate enlargement.

Digital Rectal Examination (DRE)

A diagnostic physical procedure used during prostate cancer screening to assess the prostate and rule out non-cancerous enlargement caused by Benign Prostatic Hyperplasia.

Gleason Score

A prostate cancer tumour grading system that evaluates microscopic tissue biopsy patterns to determine cancer cell differentiation, aggressiveness, and patient prognosis.

ZYTIGA

A hormone therapy medication that acts as a CYP17 inhibitor to block the production of androgens in the adrenal glands, testes, and prostate tissue.

AR Point Mutations

Point mutations in the androgen receptor gene found in 15% to 30% of hormone-resistant prostate cancer patients, most commonly located in the ligand-binding domain (LBD), allowing receptor activation irrespective of specific ligand binding.

AR Splice Variants (e.g., AR-V7)

Truncated variants of the androgen receptor, such as AR-V7, that lack the ligand-binding domain and remain localized in the nucleus under androgen-deprived conditions, displaying constitutive activity.

EZH2

A histone methyltransferase that places repressive epigenetic marks on the androgen receptor (AR) promoter, leading to AR silencing and the development of androgen-independent prostate cancer.

Outlaw Pathway

A mechanism of hormone therapy resistance in prostate cancer where non-steroid molecules, such as growth factors (IGF-1, EGF) and cytokines (IL-6), directly phosphorylate and activate the androgen receptor in a ligand-independent manner.

Breast Cancer

A malignancy originating from the epithelial tissues of the ducts or lobules of the breast, classified as locally advanced or metastatic based on disease spread.

HER2-Positive Breast Cancer

A subtype of breast cancer occurring in 15% to 25% of cases that overexpresses human epidermal growth factor receptor 2, grows more rapidly, and is managed with targeted drugs such as trastuzumab.

Triple-Negative Breast Cancer

A subtype of breast cancer representing approximately 15% of cases that lacks expression of estrogen receptors (ER-), progesterone receptors (PR-), and HER2.

Estrogen Receptor Alpha (ERα)

An estrogen receptor isoform encoded by the ESR1 gene on chromosome 6q25.1, predominantly expressed in classical estrogen target organs such as the uterus, mammary gland, bone, and cardiovascular system.

Estrogen Receptor Beta (ERβ)

An estrogen receptor isoform encoded by the ESR2 gene on chromosome 14q22-24, expressed mainly in non-canonical tissues including the ovaries and urinary tract.

Selective Estrogen Receptor Modulators (SERMs)

A class of ER pathway inhibitors (such as Tamoxifen and Raloxifene) that bind directly to ER to create an inactive complex, exerting tissue-specific agonist or antagonist responses.

Selective Estrogen Receptor Degraders (SERDs)

A class of ER pathway antagonists (such as Fulvestrant and Elacestrant) that bind ER to form an unstable complex, targeting the receptor for proteasomal degradation.

Aromatase Inhibitors (AIs)

A group of ER pathway targeted drugs (such as Arimidex, Femara, and Aromasin) that block the conversion of androgens into estrogens, reducing systemic endogenous estrogen synthesis.

Tamoxifen

A SERM that functions as an ER antagonist in breast and brain tissue to inhibit cell proliferation, but acts as an ER agonist in the liver, bone, and uterus.

Raloxifene

A SERM indicated for reducing invasive breast cancer risk and preventing osteoporosis in postmenopausal women, functioning as an ER agonist in bone and heart tissue while acting as an antagonist in breast and uterine tissues.

Study of Tamoxifen and Raloxifene (STAR)

A landmark clinical trial in high-risk postmenopausal women establishing that Raloxifene is as effective as Tamoxifen in reducing invasive breast cancer incidence by about 50%, while causing fewer uterine cancers and blood clots.